1. Field of the Invention
The present invention relates to an automatic steering device for a vehicle which minimizes the interference between an automatic steering control operation and a power steering control operation.
2. Description of the Related Art
Japanese Patent Application Laid-open No. 9-193691 (JP '691) discloses a system wherein control of an electric motor for a power steering device is switched between a normal power steering mode for assisting the driver during a steering operation and an automatic steering mode for automatic steering of a vehicle into a predetermined area, such as a garage, or in parallel parking the vehicle into a parking spot. In the automatic steering mode, the automatic steering is performed based on a relationship between a pre-stored moving distance of the vehicle and a turning angle of wheels.
In the system described in JP '691, when the driver applies a steering torque to a steering wheel during the automatic steering control, the steering torque is detected and the automatic steering control is terminated. At that time, interference between the steering operation by the driver and the automatic steering control results in a rather uncomfortable feeling to the driver. Also, when the interference terminates the instant the automatic steering control is terminated, there is yet another uncomfortable feeling sensed by the driver.